How long does a boiler last?

A well-serviced gas boiler lasts about 15 years. A neglected one might give you 8. The average UK boiler is replaced at around 12.

That's the range. Where yours falls depends almost entirely on whether it's been serviced every year, and whether the system was flushed properly when it went in.

The 50% rule

The rule of thumb engineers use: if a repair costs more than half the price of a new boiler, and the boiler is over 10 years old, replace it.

A new heat exchanger on a 14-year-old boiler is money you will spend again, because the next part is already queueing up behind it. The same money put towards a replacement buys you a 10-year warranty and a lower gas bill.

Warning signs it's on borrowed time

Breaking down more than once a year. Taking longer to heat water than it used to. Making noises it didn't used to make. Needing the pressure topped up every few weeks. Radiators that take forever to warm up.

Any one of those on its own is fixable. Two or three together, on a boiler past 10, and you're feeding money into something that's already dying.

The annual service is not optional

Most manufacturer warranties are void without one. That's the actual reason to do it. The efficiency and safety benefits are real, but the warranty is the thing you lose if you skip it, and a major failure with no cover behind it costs many times what the service did.

Book it in summer. Every engineer in the country is booked solid the first week it gets cold.